Hydraulic draft gear for railway cars



March 30, 1965 F. w. SHIREY HYDRAULIC DRAFT GEAR FOR RAILWAY CARS 10 Sheets-Sheex 1 INVENTOR. FRANK W. SHIREY @M A70/WWE) www" Filed Dec. 10, `19,62

F. W. SHIREY HYDRAULIC DRAFT GEAR FOR RAILWAY CARS March 30, 1965 l0 Sheets-Sheet 2 Filed Dec. 10, 1962 INVENTOR. FRANK W. SHIREY Amm/vg l March 30, 1965 F. w. sHlREY HYDRAULIC DRAFT GEAR FO RAILWAY CARS l0 Sheets-Sheet 5 Filed Dec. 10, 1962 INVENTOR. FRANK W. SHIREY BY, @Q

AFDRQ/ March 30, 1965 F. w. sl-llREY 3,175,700

HYDRAULIC DRAFT GEAR FOR RAILWAY CARS Filed Dec. 10, 1962 10 Sheets-Sheet 4 INVENTOR. FRANK W. SHIREY BY HUM March 30, 1965 1.-. w. SHIREY 3,175,700

eeeeeeeeeeeee 1 5 N O` N RRRRRRRRRRR EY March 30, 1965 F. w. sHlREY HYDRAULIC DRAFT GEAR FOR RAILWAY CARS 10 Sheets-Sheet 6 Filed Dec. l0, 1962 [Il WUI.

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INVENTOR. FRANK W. SHIREY Ana/wey March 30, 1965 F. w, sHlRI-:Y 3,175,700

IC DRA T Filed Dec. 10 Sh eeee -Sheex '7 INVEHVTOR. FRANK W. SHIREY March 30, 1965 F. w. SHIRE-Y HYDRAULIC DRAFT GEAR FOR RAILWAY CARS 10 Sheets-Sham 8 Filed Dec. 10, 1962 MON MON March 30, 1965 F. w. SHIREY 3,175,700

HYDRAULIC DRAFT GEAR FOR RAILWAY CARS Filed Dec. 1o, 1962 1o sheets-she@` 9 INVENTOR. FRANK W. SHIREY BY Arran/v9' March 30, 1965 F. w. sHIRI-:Y 3,175,709

HYDRAULIC DRAFT GEAR FOR RAILWAY CARS Filed Dec. 10, 1962 10 Sheets-Sheet 10 INVENTOR. FRANK w. SHIREY Ammms/ lhunwl 00N www I I I W /rm IIN INI I S mm- III/IIIII II III.

@mi mm1 @mi United States Patent 3,175,7ill HYDRAULIC D'IGE FUR RAEJWAY CARS Frank W. Shirey, Irwin, Pa., assigner to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Filed Dec. 10, 1962, Ser. No. 243,320

I4 Claims.` (Cl: 213-43) This invention relates to a combined hydro-pneumatic and spring type of draft gear for a railway freight car, and more particularly to a variable travel cushioned draft gear so selectively controlled automatically that the cushioning travel of the draft gear provided when lthe car is uncoupled from a train and is being humped in a railway classification yard is substantially greater than when the car is coupledinto the train and the train brake pipe charged to the normal fluid pressure.

Experience has shown that a considerable amount of the damage that is inflicted upon fragile lading carried by freight'cars occurs, for example, during humping operations when a car, after passing over the hump and traveling at a speed between ten and fourteen miles per hour, strikes a stationary car or a string of coupled stationary cars on the same track on which the bumped car is traveling. Furthermore, the shock resulting from the force produced by the moving car striking the stationary car or cars is often of such magnitude as to inict damage not only to the fragile lading within the car but also to the structure of the car. Such double damage is very expensive and therefore undesirable to therailroad concerned.

Accordingly, it is the general purpose of this invention to provide a novel, small, lightweight and relativ-ely low cost combined hydro-pneumatic and spring type of cushioned freight car draft gear selectively controlled so as to have a substantially longer travel when the car is being humped in a railway classification yard than when it is coupled into a train and traveling between terminals.

According to the present invention, there is provided a variable travel cushioned draft gear employing the combination of a spring, an air compressing piston and a hydraulic snubbing mechanism in which the length of travel of the draft gear is selectively controlled to provide a minimum or a maximum of travel accordingly as the brake pipe of the conventional freight car brake equipment is at its normal fluid pressure or at a reduced pressure such as that which occurs when an emergency brake application is effected.

In the accompanying drawings:

FIG. l, FIG 1A and FIG. 1B, when taken together such that the right-hand edge of FIG. 1 is matched with the left-hand edge of FIG. 1A andthe right-hand edge of FIG. 1A is matched with the left-hand edge of FIG. 1B, constitutes an elevational sectional view of a rst embodiment of a novel hydraulic draft gear device for a railway freight car.

FIG. 2 is a horizontal cross-sectional view of a cutout cock shown in FIG. l showing the communication established while the cut-out cock is in its open position.

FIG. 3 is an elevational cross-sectional view, taken along the line 3 3 of FIG. l and looking in the direction of the arrows, showing how the shank of a freight car coupler is operatively connected to a yoke of a draft gear device.

FIG. 4 is an elevational cross-sectional View, taken along the line 4--4 of FIG. 1B and looking in the direction of the arrows, showing how a hydraulic fluid reservoir is constructed so as to be disposed about the hydraulic draft gear device and between the opposite inside wall surfaces of the verticalsides of the usual center sill of the freight car.

FIG. 5 is a plan view, partly in section, taken along the line 5-5 of FIG. 1B and looking in the direction of r'ice the arrows, showing a rear draft lug secured to` each of the vertical sides of the usual center sill of the freight car to act as a stop for the hydraulic fluid reservoir and the draft gear cylinder secured thereto upon the application of a buff force to the draft gear device.

FIG. 6, FIG. 1A and FIG. 1B, when taken together such that the right-hand edge of FIG. 6 is matched with the left-hand edge of FIG. lA and the iight-hand edge of FIG. 1A is matched with the left-hand edge of FIG. 1B constitutes an elevational sectional view of a modified form of hydraulic draft gear device constructed in accordance with a second embodiment of the invention.

FIG. 7 is a plan view in section, taken along the line 77 of FIG. 6, showing certain details of construction not made apparent in FIG. 6.

FIG. 8, FIG. 8A and FIG. 8B, when taken together such that the right-hand edge `of FIG. 8 is matched with the left-hand edge of FIG. 8A and the right-hand edge of FIG. 8A is matched with the left-hand edge of FIG. 8B constitutes an elevational sectional view of a novel hydraulic `draft gear device for a railway freight car constructed in accordance with a third embodiment of the invention.

FIG. 9 is an elevational cross-sectional view, taken along the line 9 9 of FIG. 8B and showing how a horizontal type of draft gear yoke is supported for slidable movement on a plurality of angle brackets secured to the opposite inside vertical sides -of the usual center sill of a freight car, and how the draft gear cylinder is disposed between the opposite sides of a horizontal type of draft gear yoke and supported on a draft gear carrier that is secured to flanges formed at the lower ends of the vertical sides of the center sill.

FIG. l0 is a partial elevational sectional view of a novel hydraulic draft gear device for a railway freight car showing how the area of an orice through which hydraulic uid flows upon operation of the draft gear is varied in accordance with the load on the freight car.

FIG. 11 is an enlarged elevational cross-sectional view, taken along the line lll-1l of FIG. l0 and looking in the direction of the arrows, showing certain details of construction not made apparent in FIG. l0.

Description-FIGS. 1 to 5 In FIGS. l, 1A, 1B, 2, 3, 4 and 5 of the drawings is shown a variable travel cushioned draft gear device constructed in accordance with one embodiment of the invention. This draft gear device is carried in an elongated yoke pocket or slot 1 formed between parallel and spacedapart top and bottom horizontal walls 2 and 3 of a draft gear yoke 4. The left-hand end of the draft gear yoke 4 is provided, as shown in FIG. l, with a substantially rectangular shaped elongated cavity 5, open at its left-hand end, in which is received a hollow shank 6 of a railway freight car coupler, the head of which has been omitted from the drawings since it forms no part of the invention." The right-hand end of the hollow shank 6 is closed by a wall 7 that abuts a shank contact web S that is formed integral with the draft gear yoke 4. As shown in FIG. l, the wall 7 has formed on the 1eft-hand side thereof a boss 9 against which abuts one side of a substantially rectangular-shaped shank pin 10. By referring to FIG. 3, it will be seen that the substantially rectangular-shaped shank pin It) extends through a pair of aligned substantially rectangular holes Il formed respectively in a pair of spaced-apart vertical parallel walls l2 and 13 adjacent the left-hand end of the draft gear yoke 4 and through a pair of aligned substantially rectangular holes 14 formed respectively in a pair of spaced-apart vertical parallel walls 15 and 15a of the hollow shank 6. The shank pin lil is retained in place by a Cotter pin 16a. The shank pin 10 thus provides an operative connection between the draft gear yoke 4 and the hollow shank 6 of the car coupler through which draft and buff forces are transmitted. lt will be noted from FIGS. 1 and 3 that the size of the holes 11 and 14 are slightly greater than the size of the shank pin to conform with standard practice on American railroads since the shank pin 10 is made by the process of forging and the holes 11 and 14 are punched respectively in the draft gear yoke 4 and hollow shank 6.

As shown in FIG. l of the drawings, the left-hand end of the top and bottom horizontal walls 2 and 3 of the draft gear yoke 4 are joined by a follower web 16 which has formed on the right-hand side thereof a boss 16a. Disposed between the shank contact web S and the follower web 16 is a third web 17 which, in cooperation with the follower web 16, forms in the draft gear yoke 4 a cavity 18 from the bottom of which opens an elongated slot 19. Extending through each of the opposite vertical sides of the draft gear yoke 4 and opening into the cavity 18 is a rectangular opening 19a for a purpose hereinafter explained, the cavity 13 and opening 19a cooperating to form a second slot in the draft gear yoke 4.

After the hollow shank 6 of the car coupler has been secured -to the draft gear yoke 4 by the shank pin 10, a hollow box-like striker 20, having extending therethrough a rectangular shaped opening that is slightly larger in cross section than the cross section of the draft gear yoke 4, is slipped over the right-hand end of the draft gear yoke 4 and moved in the direction of the left hand until the left-hand end of the striker is substantially in alignment with the left-hand end of the draft gear yoke 4. The striker 20 is allowed to rest in this position on the draft gear yoke 4 until a draft gear device hereinafter described is assembled and then placed in the yoke pocket 1. Thereafter, the draft gear device and the yoke 4.are placed in a center sill pocket 21 of a center sill 22 also hereinafter described. The striker 2li has formed integral therewith a pair of front draft gear lugs (not shown) which are identical with the front draft lugs hereinafter described in connection with FIG. 6 of the drawings.

Formed integral with the lower side of the striker 20, as shown in FIG. 1 of the drawings, is an interlock cylinder casing 23 that has a vertical axis perpendicular to and intersecting the longitudinal axis of the draft gear yoke 4.

The interlock cylinder casing 23 is provided with a bore 24 and a coaxial counterbore 25 which opens at the lower end of the interlock cylinder casing 23. Slidably operable in the counterbore 25 in the interlock cylinder casing 23 is a iluid pressure actuated piston 26.

A release spring 27 is interposed between the piston 26 and a shoulder 23 formed by the upper end of the counterbore 25. The spring 27 serves to yieldingly bias the piston 26 and a piston rod 29 formed integral therewith to the position in which they are shown in FIG. 1 in which the end of the piston rod 29 is disposed slightly below the elongated slot 19.

A packing cup 30 of the snap-on type is secured to the pessure face of the piston 26. The packing cup 3th, when the piston 26 occupies the position in which it is shown in FIG. 1, contacts a plurality of lugs 31 which are formed integral with a pressure head 32 that closes the lower end of the counterbore 25 and is secured -to the interlock cylinder casing 23 by any suitable means (not shown). A pressure chamber 33 is thus formed between the pressure head 32 and the packing cup 30 carried by the piston 26 to which chamber fluid under pressure may be supplied through a screw-threaded port 34 and a short piece of pipe or nipple 35 having screw threads at each end thereof, one end being screw threaded into the screw threaded port 34. Screw threaded onto `the exterior threaded end of the pipe or nipple 35 is the outlet end of a vented type of cut-out cock 36 having a two-position handle 37. A pipe 38 has one end connected to the inlet end of the cut-out cock 36 and the oppositt: 6nd Gonnected to a brake pipe 39 that extends from end to end of the freight car.

While the handle 37 occupies the position in which it is shown in FIGS. 1 and 2, the cut-out cock 36 establishes a communication between the pipe 38 and the short pipe or nipple 35 whereupon the pressure chamber 33 is charged to the same pressure as is present in the brake pipe 39. Whenever the handle 37 is turned from the position in which it is shown in FIGS. 1 and 2 to a position indicated by a broken line 37a in FIGS. 1 and 2, communication is closed be-tween the brake pipe 39 and the pressure chamber 33 via the short pipe or nipple 35 and this chamber 33 is vented to atmosphere via the short pipe or nipple 35 and the vented type cut-out cock 36 so that the piston 26 and piston rod 29 will be biased by the spring 27 to the position in which they are shown in FIG. l.

The hereinbefore-mentioned center sill 22 may be fab- `ricated by welding together, as shown in FIG. 4'of the drawings, two oppositely arranged American Association of Railroads Z-sections 4t) and 41 so as to form the hereinbefore-mentioned center sill pocket 21.

The hereinbefore-mentioned draft gear device is constructed and assembled as follows:

First, a hydraulic draft gear cylinder 42 having a bore 43 extending therethrough is provided, as by a drilling operation, with two coaxial passageways 44 and 45 located as indicated in FIGS. 1B and 4. One end of each of these passageways opens at the surface of the bore 43 and the opposite end opens at the peripheral surface of the hydraulic draft gear cylinder 42.

Next, the hydraulic draft gear cylinder 42 is provided,

' as by a second drilling operation, with a pair of diametrically opposite bores 46 and 47 (FIG. 1B) for receiving therein dowel pins hereinafter described,

After completing the drilling operations, a two-compartment interconnected hydraulic liquid reservoir 43, shown in FIGS. 4 and 5, is welded to the hydraulic draft gear cylinder 42, the two compartments being connected to the interior of the Ibore 43 of this cylinder by the passageways 44 and 45. From FIG. 4 it can be seen that the hydraulic liquid reservoir 48 is formed by two oppositely arranged standard U-channels 49 and 50 each of which has the outer edge of its upper and its lower flanges welded to the outer periphery of the hydraulic draft gear cylinder 42, as indicated by the numeral 51, along the entire length of these flanges. As shown in FIG. 5, the left-hand end of the hydraulic liquid reservoir 48 is closed by a pair of substantially C-shaped end members 52 welded to the corresponding end of the U-channels 49 and 50 and to the `outer periphery of the hydraulic draft gear cylinder 42. The upper ends of the C-shaped end members A52 appear in FIG. 5 of the drawings.

The right-hand end of the hydraulic liquid reservoir 48 is closed by an end plate 53 which is first welded to the right-hand end of the hydraulic draft gear cylinder 42 to close the right-hand end of the bore 43 therein and then welded to the corresponding end of the U-channels 49 and 50. The opposite ends of end plate 53 appear in FIG. 5.

The hydraulic liquid reservoir 48 -is provided with a screw-threaded bore 54 (FIG. 4) for receiving a screwthreaded filler plug 55 which, when removed, provides for the insertion therethrough, and -through a coaxial opening 56 formed in any suitable manner in the Association of American Railroads Z-section 40 of the spout of an oil can so that the hydraulic liquid Yreservoir 48 can be filled with liquid, such as a suitable kind of oil.

Furthermore, the hydraulic liquid reservoir 4S is provided with a Valve mechanism 57 which may be similar to the well-known air lling valve mechanism used for inilating automobile tires, so that a 4chamber Sti-above the level of the oil in the reservoir, subsequent to the introduction of the oil into the reservoir, may be charged with such as air under pressure to any desired pressure by connecting a pump or other source of air under the valve mechanism 57.

Following construction of the hydraulic liquid reservoir 4S in the manner described above, a washer or spring seat 59, shown in FIG. l, is Welded or otherwise secured to the left-hand end of a metering rod 60 that appears in FIGS. 1, 1A and 1B of the drawings. The design of the metering rod 60 is congured or contoured to provide a bidirectional taper thereon, as shown in FIG. 1B, to produce a substantially rectangular force displacement curve for the draft gear device action. After the spring seat 59 is welded to the metering rod 6i), a spring `61 is slipped over the right-hand end ofthe metering rod 60 and moved in the direction of the left hand until the left-hand end thereof rests against the spring seat `59.

Next, a hydraulic oriiice in the form of 4a bushing 62, shown in EFIG. 1B as having at one end a collar 63, is press-fitted into a bore 64 that extends through a cylindrical member `65 that has a counterbore 66 coaxial with the bore 164, the diameter of fthe counterbore 66 being slightly greater than the diameter of the collar 63 which is disposed within the counterbore so as to rest against the bottom thereof. Two diametrically opposite and coaxial counterbores `67 of the same diameter as the bores 46 and 47 in the hydraulic draft gear cylinder 42 are now drilled in the periphery of the cylindrical member 65.

Subsequent to assembling the bushing 62 to the cylindrical member 65 in the manner described above, the righthand end of the metering rod 60 is inserted through the collar end of `the bushing 62, it being noted from FIG. 1B that the inside diameter of the bushing is greater than the outside diameter ofthe metering rod thereby providing an orifice for the -ow therethrough of a hydraulic vliquid in a manner hereinafter described in detail. The size of this oriice can be increased by using a metering rod of smaller diameter or decreased by using a metering rod of larger diameter to provide an orice size that corresponds to the gross weight of the particular car upon lwhich the draft gear device is used.

After the right-hand end of the metering rod 60 has been inserted through the bushing 62, a force is next applied to the cylindrical member 65 by any suitable means to compress the spring 61 and move the cylindrical member d5 toward the spring seat 59 (FIG. 1) until a piston 63 having a central bore 69 can be slipped onto a portion 70 of reduced diameter formed on the right-hand end of the metering rod 60, as shown in FIG. 1B, and moved in the direction of the left hand until the left-hand `face of the piston 63 'abuts a `shoulder 71 formed on the metering rod 6,@ at the left-hand end of the portion 70 of reduced diameter, it being understood that an O-ring seal 72 has been previously inserted in an internal groove `formed in the wall of the `central bore 69. The right-hand fa-ce of theV piston 68 is Iprovided with a counterbore 73 which is somewhat larger in diameter than a nut 74 that is now screwed onto screw threads 75 `formed on the right-hand half of the portion 70 of reduced diameter and tightened by means `of a Spanner wrench. The force applied to the cylindrical member 615 may now be removed whereupon the spring 61 will be rendered effective to bias the right-hand side or the cylindrical member 65 against the left-hand face of the piston 68.

As shown in FIG. 1B of the drawings, the periphery of the piston 68 is provided vwith four spaced-apart peripheral annular grooves Therefore, prior to placing the'piston 68 in the bore 43 of the hydraulic dra-ft gear cylinder 42, an O-ring seal 76 is inserted in each of these `four peripheral annular grooves in the piston.

`Subsequent to securing the piston 68 to the one end of the `metering rod 160 and inserting the O-ring seals 7d in theV grooves in the piston in the manner just explained, the piston 68 is introduced into the left-hand end of the bore 43 in the hydraulic draft gear cylinder 42. The assembly, which includes the piston 68, spring 6d, metering rod 66, spring seat S9, and cylindrical member 65 pressure to d is then pushed in the direction of the right hand until the cylindrical member 65 reaches the position in which it is shown in FG. 11B in which the counterbores 67 are in alignment `with the bores 46 and 47 in the hydraulic draft gear cylinder 42, it being understood that the assembly may be rotated aboutthe longitudinal axis of the metering rod 69 to obtain this alignment, if necessary.

With the counterbores 67 in the cylindrical member 65 thus in alignment with the bores 46 and 47 in the hydraulic draft gear cylinder 42, a dowel pin 77 is pushed, or driven if necessary, into each of the bores 46 and 47 and the corresponding counterbore 67 after which the outer ends of the dowel pins 7'7 are welded to the hydraulic gear cylinder 42, it being noted that the length of the dowel pins 77 is less than the combined lengta of the bore and counterbore in which they are disposed. lf desired, the bores and counterbores could be screw threaded and hexagon socket-type set screws used in place of the dowel pins 77.

As shown in FIG. 1A of the drawings, the left-hand end of the hydraulic draft gear cylinder 42 is provided with a counterbore 78 in which is now placed a wiper or Scraper element 79 to prevent the entrance of dust and dirt.

Subsequent to placing the wiper or scraper element 79 in the counterbore 78, a cup-shaped plunger Si) is prepared to be slidably mounted in the left-.hand end of the bore d3 in the hydraulic draft gear cylinder 42. The plunger 89 is chrome plated to prevent rusting since its left-hand end is exposed to the atmosphere. The righthand end of the cup-shaped plunger 8f) is provided with a portion 31 of reduced diameter, a part of which is provided with external screw threads. A plurality of segments of high pressure packing 32 is first placed on the portion 81. of reduced diameter after which a nut 83 is screwed onto the threaded end of the cup-shaped plunger 8@ to retain the high pressure packing thereon.

To the left of the high pressure packing 82 the plunger 3d is provided with six spaced-apart peripheral annular ooves in each of which is now inserted an O-ring seal 'lhe cup-shaped plunger Sti is now slipped over the spring seat 59 (FIG. l) on the left-hand end of the metering rod 60 and moved in the direction of the right hand so that the right-hand end thereof may be introduced into the bore 43 in the hydraulic draft gear cylinder 42 by pushing it through the wiper or scraper element 79 carried in the counterbore 7S in the left-hand end of the hydraulic draft gear cylinder and thereafter moving the cup-shaped plunger 8@ in the direction of the right hand until the bottom thereof abuts the spring seat S9.

The parts so far assembled include the hydraulic draft gear cylinder d?. to which has been Welded the hydraulic liquid reservoir 4S, the piston 68, the metering rod 60 to the left-hand end of which is welded the spring seat 5?, the cylindrical member o5 Which carries the bushing 62 and which is anchored to the hydraulic draft gear cylinder` 42 by the dowel pins '77, the plunger Si), and the spring 61 that is interposed between the spring seat 59 and the collar 6,3 on the bushing 62 and which, at this time, is effective to bias the left-hand face of the piston 68 against the right-hand end of the cylindrical member 6ta' so that the piston 63 is in a position to close that end of the passageways i4 and 45, shown in FIG. 4, that opens at the surface of the bore d3 in the hydrauiic draft gear cylinder 42.

In order to move the piston 63 to the position in which it is shown in FIG. 1B of the drawings in which that end of the passageways d4 and 45 that opens at the surface of the bore 53 in the hydraulic draft gear cylinder 42 is uncovered by the piston dit, the parts so far assembled are next placed in a jig. This jig may comprise a ilat surface, such as a rectangular platform, having at one end a vertical stop member against which is placed one end of the assembly which, for example, may be the lefthand end of the cup-shaped plunger 80 shown in FIG. 1. This jig may further comprise a iiuid motor secured to the opposite end of the rectangular platform in sucha position that the exterior end of a piston rod of the fluid motor will be moved into abutting relationship with the end plate 53 of the hydraulic liquid reservoir 48 upon a small increment of movement of a piston, disposed in the uid motor and secured to the interior end of the piston rod, in response to the supply of fluid under pressure to the fluid motor. If, after the exterior end of the piston rod of the iiuid motor has moved into abutting contact with the end plate 53 of the assembly now in the jig, the supply of tluid under pressure to the tluid motor is continued, this fluid under pressure will be effective on the piston disposed within the fluid motor to move this piston and the piston rod secured thereto in the direction to move the end plate 53 and thereby the hydraulic draft gear cylinder 42, cylindrical member 65 and the hydraulic liquid reservoir 48 in the direction of the left hand, as viewed in FIG. 1B, and relative to the now stationary piston 68, metering rod 68, and cupshaped plunger 88 (FIGS. 1 and 1A) until the hydraulic draft gear cylinder 42, cylindrical member 65, and the hydraulic liquid reservoir 48 are in a position in which the end of the passageways 44 and 45 that opens at the wall surface of the bore 43 in the hydraulic draft gear cylinder 42 are in a position to the left of the left-hand face of the piston 68, this end of the passageway 44 being shown in this position in FIG. 1B of the drawings. The jig may be provided with a suitable limit stop to prevent further movement of the piston rod of the iuid motor and thereby the hydraulic draft gear cylinder 42 and hydraulic liquid reservoir 48.

With the assembled parts remaining in the jig, the filler plug 55, shown in FIG. 4, is removed from the tapped bore 54 by any suitable means, such as a screw driver or socket wrench. Subsequent to removal of the filler plug 55, the spout of an oil can is inserted through the opening 56 and the tapped bore 54 and a suitable oil poured into the hydraulic liquid reservoir 48. It will be noted that the oil thus introduced into the hydraulic liquid reservoir 48 will ow through the passageways 44 and 4S to a chamber 85 formed by the wall of the bore 43 in the hydraulic draft gear cylinder 42, the left-hand face of the piston 68, and the right-hand face of the cylindrical member 65 which carries the bushing 62. Since the inside diameter of the bushing 62 is greater than the outside diameter of the metering rod 60, the oil supplied to the chamber 85 will flow therefrom through the bushing 62, which constitutes a hydraulic orifice, to a chamber 86 formed by the wall of the bore 43, the left-hand face of the cylindrical member 65, and the interior of the cup-shaped plunger 80. Oil is thus added to the chambers 85 and 86 and the hydraulic liquid reservoir 48 until the oil level in the latter is raised to that shown in FIG. 4, or, in other words, until the oil begins to run out the tapped bore 54.

Subsequent to filling the chambers 85 and 86 and the hydraulic liquid reservoir 48 with oil, the filler plug 55 is replaced in the tapped bore 54 and tightened therein.

Thereafter, an air pump or another suitable source of air under pressure is connected to the valve mechanism 57 and the chamber 58 charged with air under pressure to a chosen pressure that is less than that required to move the piston 68 in the direction of the right hand from the position in which it is shown in FIG. 1B of the drawings, but great enough to insure that chamber 85 is always maintained full of oil and the level of the oil in the hydraulic liquid reservoir 48 does not rise above the level shown in FIG. 4 by tlow through the passageways 44 and 45 from the chamber 85 while oil is being forced from chamber 86 to the chamber 85 at a rate controlled by the size of hydraulic orifice 62 while the piston 68 is moving in the direction of the right hand from the position in which it is shown in FIG. 1B in a manner hereinafter described in detail to effect an increase in the pressure of air in an air chamber 87 formed by the Wall of the bore 48, the right-hand face of the piston 68, andthe end plate 53.

The volume of the air chamber 87 may be such as to provide approximately a ratio of compression of 1l to 1 when the piston 68 makes its maximum stroke in the direction of the right hand from the position in which it is shown in FIG. 1B lof the drawings.

The assembly may now be removed from the jig since the oil under pressure in the chambers and 86 will prevent movement of the piston 68 in the direction of the left hand, as viewed in FIG. 1B, by the spring 61.

Next, one of a pair of L-shaped rear draft lugs 88 each having six spaced-apart parallel strengthening ribs 89, as shown in FlG. 1B of the drawings, is welded to the vertical inside face of the respective American Association of Railroads Z-sections 48 and 41 as shown in FIG. 5.

Subsequent to welding the rear draft lugs 88 to the American Association of Railroads Z-sections 48 and 41, a follower 98 (FIG. l), the length of which is substantially equal to the distance between the vertical inside faces of the American Association of Railroads Z-sections 49 and 41, is placed in the yoke pocket 1 so that the left-hand side thereof abuts the boss 16a formed on the right-hand side of the follower web 16 and the opposite ends thereof extend an equal distance beyond the walls 2 and 3 of the draft gear yoke 4.

After the follower 98 has been thus placed in the yoke pocket 1, the draft gear device including the previously assembled hydraulic draft gear cylinder 42 and the cylindrical member 65 secured thereto, the piston 68 therein, the metering rod 68 and spring seat 59 secured thereto, the spring 61, the plunger 80, and the hydraulic liquid reservoir 48 which is welded to the hydraulic draft gear cylinder 42, as has been hereinbefore explained, are positioned in the yoke pocket 1 between the walls 2 and 3 of the draft gear yoke 4 so that the right-hand side of the end plate 53 abuts the end of the yoke 4 at the right-hand end of the yoke pocket 1, as shown in FIG. 1B, and the left-hand end of the plunger 88 abuts the right-hand side of the follower 911, as shown in FIG. 1 of the drawings, it being understood that the draft gear device is so located in the yoke pocket 1 that the longitudinal axis of the hydraulic draft gear cylinder 42 lies in a vertical plane that passes through the yoke 4 midway the width of the walls 2 and 3.

The yoke and draft gear device are now ready to be placed in the center sill pocket 21. To do so, the hydraulic liquid reservoir 48 is introduced into the left-hand end of the center sill pocket 21, it being noted from FIG. 4 that the width of the center sill pocket 21 is slightly greater than the width of the hydraulic liquid reservoir 48. After the yoke and draft gear device are introduced int-o the left-hand end of the center sill pocket 21, the entire assembly is moved in the direction of the right hand until the end plate 53 abuts the rear draft gear lugs 88 as Ishown in FIG. 5 of the drawings.

Now, while the assembly is supported by any suitable means, a pair of parallel and identical draft gear carriers 91, which appear in FIGS. 1B and 4, are placed beneath the yoke 4 and riveted at their opposite ends to feet 92 and 93 of the respective Association of American Railroads Z-sections 4@ and 41 by rivets 94. After the riveting operation has been completed, the supporting means may be removed from beneath the yoke 4 for the yoke 4 will now be supported by the draft gear carriers 91.

Following removal of the supporting means from beneath the yoke 4, the hereinbefore-mentioned striker Ztl is moved from the position in which it was placed, adjacent the left-hand end of the yoke 4 in the direction o-f the right hand, as viewed in FIG. 1, along the yoke 4 until the right-hand end thereof can be Vinserted into the lefthand end of the center lsill pocket 21, after which the striker 219 is pushed into the center sill pocket 21 until g. the striker occupies the position in which it is shown in FIG. 1. With the striker in this position, it is welded to the left-hand end of the center sill 22, as indicated by the reference numeral 95 in FIG. 1. In this position of the striker 20, the right-hand `side of the front draft gear lugs that are integral therewith abut the respective lefthand side of the opposite end portions of the follower 90.

It will be understood that the center sill 22 constitutes a part of the body of a railway freight car according to standard methods of freight car construction.

In addition to the pair of draft gear carriers 91 shown in FIG. 1B for supporting the yoke 4 and the draft gear device carried therein, the yoke 4 is also supported by a center plate adapter 96 shown in FIG. 1A. The lower face of the center plate adapter 96 has welded thereto a standard body center plate 97. The center plate adapter 96 is provided with a bore 98 that is coaxial with a bore 99 of equal diameter in the standard body center plate 97 and a coaxial counterbore 100. Subsequent to welding the center plate adapter 96 to the standard body center plate 97, a center pin 101 is inserted into the coaxial bores 98 and 99 so that a cylindrical head 102 formed on the upper end of the center pin 101 is disposed within the counterbore 100, it being understood that the thickness of the head 102 does not exceed the depth of the counterbore 100.

After the center pin 101 has been inserted into the bores 98 and 99, as just explained, the center plate adapter 96 is placed beneath the yoke 4 in the position along the length thereof inwhich the center plate adapter 96 i-s shown in FIG. 1A. Thereafter, the opposite ends (not shown) of the center plate adapter 96 are riveted to the feet 92 and 93 of the respective Association of American Railroads Z-sections 40 and 41 by rivets (not shown).

A car truck bolster 103 is provided with a truck center plate 104 that is cast integral with `the top side of the bolster and has a central bore 105 in which is received the center pin 101. The truck center plate 104 is further pro- -vided with a cylindrical recess or groove 106 concentric with the bore 105 in which groove is received the standard body center `plate 97 whereby the car body, of which the center sill 22 is a part, is supported on the car truck bolster 103. This construction allows the car truck to turn freely under the car.

Operation It should be noted that for the same length of stroke, the capacity of the draft gear device of the present invention to absorb the kinetic energy of a moving railway vehicle, in either buff or draft, is the same. So long as the kinetic energy developed as the result of a buff or a draft impact imparted by each to the other of two adjacent railway car couplers upon the colliding `of the two cars carrying these couplers does not exceed the capacity or the amount of kinetic lenergy for which the draft gear was designed to absorb by more than a certain amount, the stress induced in the couplers and the Various parts constituting the bodies `of the cars will be limited to a value below or not in excess of the elastic limit of the materials of which the car couplers and car bodies are constructed.

It should be understood that, in draft, kinetic energy is transmitted from the car coupler through the shank pin, the draft gear yoke, the draft gear device and the front dragt lugs to the center sill and car body, and, in buff, kinetic energy is transmitted from the car coupler through the draft gear yoke, the draft gear device and the rear draft lugs to the center sill and car body.

(a) Bu impactcar detached for humping When a freight car is detached from a train for humping operations in a railway classification yard, iiuid under pressure is completely vented from the brake pipe 39 to atmosphere. Consequently, the chamber 33 (FIG.

1) in the interlock cylinder casing 23 is likewise vented to the atmosphere via short pipe or n-ipple 35, vented type cut-out cock 36, pipe 38, and the brake pipe 39 extending from end to end of the freight car, it being understood that the handle 37 of the cut-out cock 3o occupies the position in which it is shown in FIGS. 1 and 2, in which position a communication isl established between the short pipe or nipple 35 and the pipe 38. Upon completely venting the fluid under pressure from the chamber 33, the spring27 is rendered effective to move the piston Z6 and piston rod 29 to the position in which they are shown in FIG. 1, in which the upper end of the piston rod 29 is completely withdrawn from the elongated slot 19 in the draft gear yoke 4.

Now let it be supposed that the detached car, While traveling along a track in the classification yard at some slow speed such as, for example, fourteen miles per hour, collides with a standing car or string of cars on this track. This moving car has a certain amount of kinetic energy. As `the couplers on the adjacent ends of the moving car and the standing car come into contact, each coupler imparts an impact to the other, the impact imparted to each coupler by the other being the same. These couplers operate automatically at this time to couple the two cars together. l

Let it be assumed that the hollow shank 6 shown in FIG. 1 of the drawings is the shank of the car coupler on a standing car that is struck by the moving car. Therefore, upon collision of the moving car with the standing car some of the kinetic energy of the moving car is transmitted from the coupler on the moving car through the hollow [shank 6 and shank contact web 8 shown in FIG. 1 to the draft gear yoke 4, it being understood that the direction of the blow imparted as a result of this impact acts in the direction of the right hand, as viewed in FIGS. 1, lA and 1B of the drawings. Consequently, the draft gear yoke 4 will be moved in the direction of the right hand relative to the center sill 22 as the result of the moving car striking the standing car.

As shown in FIG. 5 of the drawings, the right-hand side of the opposite end portions of the end plate 53 that extend beyond the opposite sides of the draft gear yoke 4 normally abut the respective rear draft lugs 88 that are welded to the center sill 22 as hereinbefore mentioned. Therefore, the hydraulic draft gear cylinder 42, which has the cylindrical member 65 secured therein by the dowel pins 77, and the hydraulic liquid reservoir 40 are prevented from moving in the direction of the right hand, relative to the center sill 22, upon movement of the draft gear yoke 4 in this direct-ion since the hydraulic draft gear cylinder 42 and the reservoir 48 are welded to the end plate 53, as hereinbefore mentioned.

The movement of the draft gear yoke 4 in the direction of the right hand, as Viewed in the drawings, is transmitted through the follower web 16 and boss 16a (FIG. 1) which are integral with the yoke 4 to the follower 90 and thence to the plunger 80. The cup-shaped plunger extends telescopically into the left-hand end of the hydraulic draft gear cylinder 42;, which is now stationary relative to the center sill 22, and abuts the left-hand end of the metering rod 60 as shown in FIG. 1. Since the piston 68 is secured to the right-hand end of the metering rod 60 as shown in FIG. 1B, it will be apparent that as the draft gear yoke 4 is moved in the direction of the right hand, the follower 90, plunger 80, metering rod 60 and piston 60 are moved therewith against the yielding resistance of the spring 61, and with respect to the now stationary hydraulic draft gear cylinder 42 and the cylindrical member 65 anchored thereto.

Thisl movement of the plunger 80, metering rod 60 and the piston 60 is effective to simultaneously increase the volume of the chamber 05 and decrease the volume of the chambers 86 and S7. As the plunger 00 is thus moved in the direction of the right hand, it is effective to force the oil in the chamber 86 to flow through the orifice constituted by the bushing 62 through which the metering rod 66 extends to the chamber 85. l It is apparent from FIG. 1B that the oil ow initiated by movement of the plunger tt) in the directlon of the right hand is from the high pressure chamber 86 through the orifice constituted by the bushing 62 and metering rod 60 and into the chamber 85, the volume of which is increasing at the same rate as the volume of the chamber 36 is decreasing.

The oil llow through the orifice is at a relatively high velocity and creates great turbulence in the chamber 8S. This great turbulence is caused at least in part by the high velocity oil impinging directly against the left-hand face of thepiston 63, and is responsible for dissipation of much of the kinetic energy of the oil in the form of heat. It will be understood that as the piston 66 moves in the direction of the right hand from the position in which it is shown in FIG. 1B, the effect of the impingement of the oil on this piston decreases.

Movement of the piston 63 in the direction of the right hand, as viewed in FIG. 1B, is effective to decrease the volume of the chamber 87 and increase the pressure of the air in this chamber. As is well known, the compression of air from a lower pressure to a higher pressure by effecting a reduction of the volume of the air requires energy. Consequently, the compression of the air in the chamber S7 absorbs some of the kinetic energy transmitted to the car coupler, shank 6 and yoke 4 by the moving car striking the stationary car, it being understood that this kinetic energy is changed to potential energy and stored in the air under pressure in chamber 87.

Compressing the spring 6l as the plunger 80 moves in the direction of the right hand requires the absorption of some of the kinetic energy transmitted by the moving car, it being understood that this kinetic energy is changed to potential energy and stored in the spring 61.

Furthermore, the friction of the draft gear yoke 4 and the other moving parts is effective to dissipate or absorb some ofthis kinetic energy. Therefore, all the kinetic energy transmitted to the car coupler and shank 6 on each of the two colliding cars, with the exception of the potential energy stored in the springs' 61 and in the air under pressure in the chambers 87, is dissipated in the form of heat by the passing of the oil through the orifices, the turbulence in the chambers 65, and the friction of the various parts of the draft gear devices, or is transferred as kinetic energy Via the end plates 53 and rear draft lugs 88 to the center sill 22 of the respective car with its load carried in the body thereof, of which the respective center sill is a part.

The standard coupler used on freight cars is designed to withstand a predetermined buff or compression impact blow without inducing a stress therein that exceeds the elastic limit of the steel, of which the coupler is constructed. In order that the buff stress established by the impact of the two colliding cars is maintained constant during the time required for the plunger 80, metering rod 66 and the piston 63 to travel their maximum length of stroke in the bore 43 of the hydraulic draft gear cylinder 42, the area of the orifice provided by the bushing 62 and metering rod 60 must be varied so as to provide or maintain a constant oil pressure in chamber 86, which constant pressure establishes a corresponding constant force that must not exceed the allowable force that can be transmitted through the hydraulic draft gear cylinder 42 and the hydraulic liquid reservoir 48 to the rear draft gear lugs 68 and thence to the center sill 22 and car body integral therewith without iniiicting damage to the lading carried by the car.

As the plunger 80 moves in the direction of the right hand into the bore 43 of the hydraulic draft gear cylinder 42 from the position in which it is shown in FIGS. 1 and 1A at an initial velocity corresponding to the degree of the impact blow on the car coupler as the result of the `collision of the moving car with the standing car or cars,

the pressure of the oil in the chamber 86 is increased at a rapid rate due to the combined effect of the inertia of the oil in this chamber and the limited area of the orice provided by the bushing 62 and metering rod 60, through which the oil flows from chamber 86 to chamber 85. In order that thev force developed by the increase of the pressure of the oil in the chamber 86 be limited to and thereafter maintained at a value which will not induce a stress in either the coupler or car body in excess of the elastic limit, the oriiice area must be rapidly increased subsequent to the metering rod 60 moving in the direction of the right hand the distance a indicated in FIG. 1B, in which distance the pressure developed in the chamber 36 is increased to a value somewhat less than that required to induce a stress in either the coupler or car body equal to the elastic limit.

This rapid increase of orifice area is provided, for example, by forming or machining a irst taper on the metering rod 60 having the length b shown in FIG. v'1B. The length b is the distance that the metering rod 60 must travel after traveling the distance a to reduce the rate of build-up of pressure in chamber 86 to zero and thereby establish that pressure in the chamber S6 which will induce a stress in either the coupler or car body slightly less than the elastic limit.

In order to maintain the pressure thus established in the chamber 86 as the plunger 3i), metering rod 60 and piston 68 continue to move in the direction of the right hand a distance c shown in FIGS. 1A and 1B, the metering rod 6i) must be tapered this distance c, the direction of the taper c being opposite the direction of the taper b. It will be apparent that as the tapered portion c of the metering rod 66 passes through the bushing 62, the area of the orifice is decreased at a rate corresponding to the angle of the taper c. Furthermore, it will be understood that the initial velocity of the plunger 30, the metering rod 6) and piston 68 has been reduced as they moved in the direction of the right hand, as part of the kinetic energy of the striking car is absorbed in the manner hereinbefore de scribed. Therefore, in order to maintain a constant pressure in the chamber 86 as the plunger 80 and metering rod 60 move in the direction of the right hand with a constantly decreasing velocity, the area of the orifice provided by bushing 62 and the metering rod 60 must be decreased at a certain corresponding constant rate. Consequently, by providing that the direction of the taper c is opposite the direction of the taper b, this requirement that the oritice area be constantly decreased at this certain constant rate is insured.

The metering rod 66 is provided at the left-hand end of the tapered portion c with a portion d (FIG. 1A) having an angle of taper greater than the angle of taper of the portion c to insure that the pressure in the chamber 86 does not rapidly decrease as this portion d of the metering rod 60 begins to move into the orice bushing 62, since, at this time, the velocity of the metering rod 60 relative to the bushing is approaching zero. Adjacent to the tapered portion d is a portion e of constant diameter that provides an orifice of minimum area as` this portion e passes into the left-hand end of the bus-hing 62.v This orifice of minimum area insures that the rate of decrease in the pressure in the chamber 86 is minimized as the plunger 80, metering rod 60 and piston 68 reach the end of their stroke.

The contour of the metering rod 60 provided by the portions d and e insures that damage to the draft gear device and car body is minimized in the event that the kinetic energy of the striking car is in excess of the capacity of the draft gear device to absorb kinetic energy, for this increase in kinetic energy is effective to increase the pressure of the oil in the chamber 86 to a maximum value as the portion d travels through the bushing 62 and then decreases to a certain value as the portion e of constant diameter enters the leftahand end of the bushing 62 13 as the plunger S0, metering rod- 60 and piston. 68 reach theend of'theirstroke.

The pressure established inthe chamber'S in response to the plunger 80, metering rod 60 and pistonrS-,traveling in the direction of the right-1 hand .through their full length of`stroke constitutesfrarhydraulic head of oil forforcing the oil from the chamber 86? through the orifice tothe chamber 85.

The general equation for the velocity of spouting liquid is V=\/2g, where V=theoretical velocity lin feet per second, 1c-.acceleration of gravity in feet per second, and H`=head of liquidl in feet. The discharge from an orifice in cubic feet* per second isequalto the product of the actual velocityV andthe area of the jet. (The above equaf tions `are from section 2, page 07 of Eleventh Edition, Volume IL Kents Mechanical Engineeris Handbook.)

The total quantity Q of oil discharged from the orifice may be expressed by the equation Q=vt, where v represents the dischargein' cubic feet per second and t the time in" seconds that the discharge through the orifice continues.

From the above equations itis apparent that the total quantity of oil discharged from the chamber S6 through the orice to the chamber `35 is-dependent on the pressure in the chamber 86' and the length of time required for the plunger 89, metering rod 60and-piston 68 to travel the full length of their stroke. This time can be greatly increased if thelength `of stroke-of these elements is, for example, 30 inches instead of 25/8 inches, which is the length of travel of a standard frictiondraft gear device.

Increasing the length of stroke of the piston correspondingly requires'an increase in the length of air chamber 87. It follows, therefore, that as the length of the air chamber 87 and` the `length of the stroke of the piston 68 are increased, the amount of kinetic energy absorbed or chan-ged into potential energy and stored in the air under ,pressure in the chamber 87 is accordingly increased.

The amount of kinetic energy absorbed may be expressed mathematically in manner well known to those skilled in the art by use of the general equation for kinetic energy:

where m=mass=weight:-g; v =velocity in feet per second; a=acceleration in feet per second per second; t=time `in seconds.

Reference may be had to The American Society of Mechanical Engineers Paper No. 61-WA--256 covering The Design of Cushioning Gears for Rail-Car Applica- .tions by Robert L. Hassenauer and George E. Novak .presented at the Winter Annual Meeting in New York, vNew York, November 26-December 1, 1961, for a fuller explanation of the theory of an air-oil cushioning draft gearV and for a method of calculating the relative accelera- `tion between a rail car and its lading occurring as the resul-t of amoving car striking a stationary car or string of cars.

4From the above-mentioned equation for kinetic energy,

it will be appreciated that by increasing the length of stroke of the plunger 80, metering rod 60 and piston 68 from, for example, 2% inches to, for example, 30 inches, the time required for the oil to be forced from the chamber S6 .through the orifice `to the chamber 85 is accordingly increased and this increase in time is effective to increase the kinetic energy dissipated by the flow .of the oil through the orifice in accordance vw'th the square of `the time required for this flow since as stated above.

The impact blow delivered to the car coupler and shank` 6 of the standing car, as the result of the moving car traveling at a speed of, for example, fourteen miles per hour, colliding with the standing car, is effective to move the shank 6, draft gear yoke 4, follower 90, plunger 8), metering rod 66 and piston 63 in the direction of the right hand, as viewed in the drawings, relative to the hydraulic draft gear cylinder 42, hydraulic liquid reservoir 48 and rear draft gear lugs 88 until the right-hand side of the follower 90 comes into Contact with the left-hand end of the hydraulic draft gear cylinder 42. The movement of the plunger into the hydraulic draft gear cylinder 42 is effective to cause absorption of some of the kinetic ener-gy of the moving car by forcing the oil from the chamber 86 through the orice bushing 62 to the chamber in the manner hereinbefore described. This movement of the plunger 80 is effective to compress the spring 61, which compression also absorbs some of the kinetic energy of the moving car. Furthermore, the friction of the parts of the draft gear device and the compression of the air in the chamber 87 are effective to absorb some of the kinetic energy of the moving car. The remaining kinetic energy of the moving car is transmitted to the rear draft lugs 88 and thence to the center sill 22 to which the rear draft lugs 38 are Welded and upon which is supported the body of the freight car and ,the lading carried in this body. This remaining kinetic energy that is thus transmitted to the center sill 22 and the car body of the standing car is effective to move the standing car or string of standing cars if one or more cars are coupled to the struck car, provided this remaining `kinetic energy is great enough to overcome the inertia of the standing car or cars.

From the foregoing, it is apparent that the draft gear device shown in FGS. 1, 1B, 2, 3 and 4 is effective to dissipate as heat a portion of the kinetic energy of a mov- Ving freight car upon the moving car striking a standing car or string of cars by forcing liquid from the chamber 86 through a choke to the chamber 85, that another portion of this kinetic energy is stored as potential energy in the spring 61, that still another portion of this kinetic ,energy is stored as potential energy in the air under pressure in the chamber S7, and that the remainder of this kinetic energy is transferred via the end plate 53 and rear draft lugs 88 to the center sill 22 of the respective car to impart movement to the standing car or string of standing cars, if one or more cars are coupled to the struck car, provided this remaining kinetic energy is great enough to overcome the inertia of the standing car or cars. If this remainder of kinetic energy is of suthcient magnitude to overcome the inertia of the standing car or cars and impart movement thereo, this movement effects a relative `acceleration between each car and the lading in that car.

Itis apparent, therefore, that by increasing the amount of kinetic energy absorbed by the draft gear device and stored as` potential energy in the draft gear device, the amount of kinetic energy remaining to impart movement to the struck car or string of cars and effect a relative acceleration between' each car and the lading in the respective `car is correspondingly decreased. It, therefore, follows that a reduction in the amount of kinetic energy imparted to the struck car or string of cars likewise reduces the magnitude of the relative acceleration between each respective car and the lading in the car. Remembering that force is equal to the product of mass (weights-32.174 feet per second per second) and acceleration, it will be apparent that a reduction in the magnitude of the relative acceleration between the car and the lading in the car correspondingly reduces the force of impact of the lading in a standing car with the `end of this car when a moving car strikes the standing car. This reduction in the force of impact of the lading with the end of the car lessens the likelihood of damage to the lading. Accordingly, the purpose of providing `a long travel for the piston 68 of the draft gear of the l present invention is to reduce the forceA of impact on the lading carried in the car equipped with this draft gear, it being understood fronrthe foregoing that, since kinetic energy an increase in the travel of piston 68 increases the value of t in this equation and therefore the amount of kinetic energy absorbed by the draft gear.

If the amount of kinetic energy transmitted to the struck car or string of cars is great enough to overcome the inertia of the struck car or string of cars, the struck car or string of cars will move, it being understood that the couplers on the striking car and struck car operate at the time of impact to couple these cars. Subsequent to this coupling operation, the potential energy stored in the springs 6l and the air under pressure in the chambers l87 begin to re-expand upon the velocity of the two cars reaching the same value. This re-expansion is effective to restore the various parts of the draft gear devices on the cars to the position 4they occupied prior to the striking car colliding with the struck car or string of cars.

(b) Draft impact-Car coupled in a train When a car is coupled in a train, the brake pipe hose at each end of the car is coupled to the brake pipe hose on the adjacent end of the respective adjacent car in the train. Subsequent to coupling a car in a train, the brake pipe angle cocks at each end of the car are opened so that the entire train brake pipe may be fully charged to the normal pressure carried in the train brake pipe. Assuming that the handle 37 of the cut-out cock 36 on the car that has been coupled in the train occupies the position in which it is shown in FIG. 1 of the drawings, in which position it establishes a communication between the pipe 38 and the short pipe or nipple 35, fluid under pressure will flow from the brake pipe 39 via pipe 38, cut-out cock 36, and the short pipe or nipple 35 to the pressure chamber 33 below the packing cup 30. Fluid under pressure thus supplied to the pressure chamber 33 is effective to move the piston 26 and piston rod 29 up'A ward from the position in which they are shown in FIG. 1 against the yielding resistance of the spring 27 until the upper end of the piston rod 29 is disposed within the elongated slot 19 as indicated by the broken line in FIG. 1.

While the upper end of the piston rod 29 is disposed in the elongated slot 19, the travel of the draft gear yoke 4 and likewise the car coupler in bu and in draft will be retricted or reduced to the distances indicated by the corresponding legends shown in FIG. 1.

Now let it be supposed that the train is standing and the engineer desires to start the train. To do so, he moves the controller handle from idle position to a power position. This effects the supply of power to the driving wheels of the locomotive to start the locomotive from a stopped position. The initial movement of the locomotive is transmitted from the coupler at the train end of the locomotive to the coupler at the locomotive end of the first car in the train. Now let it be further supposed that the hollow shank 6 shown in FIG. 1 of the drawings is the shank of the coupler at the locomotive end of the first car in the train. Therefore, the initial movement of the locomotive is effective to exert a pull or jerk and thereby establish a force that acts in the direction of the left hand on the hollow shank 6 shown in FIG. 1. This force acting on the hollow shank 6 is transmitted through the boss 9 on wall 7 that closes the right-hand end of the hollow shank 6 to the shank pin 10. Since the shank .pin 10 extends through the holes 11 (FIG. 3) in the draft 18 of the end plate 53. Therefore,`the pull on the draft gear yoke 4 in the direction of the left hand will be transmitted through the end plate 53 to the right-hand end of the hydraulic draft gea-r cylinder 42 since the end plate 53 is Welded to this end of the cylinder.

The left-hand side of the opposite end portions of the follower 90 (FIG. 1) that extend beyond the opposite sides .of the draft gear yoke 4 normally abut, respectively, the right-hand side ofthe front draft gear lugs that are integral with the striker 20, as hereinbefore explained. Furthermore, the right-hand side of the center portion of the follower 90 normally abuts the left-hand end of the plunger as shown in FIG. 1. Therefore, upon movement of the draft gear yoke 4, end plate 53 and hydraulic draft -gear cylinder 42 in the direction of the left hand in response to the pull in this direction exerted by the locomotive on the hollow shank 6 of the car coupler, the cup-shaped plunger 80 is prevented from moving in this direction. Since the`cup-shaped plunger 80 abuts the left-hand end of the metering rod 60 and the right-hand end of the metering rod 68 has the piston 68 secured thereto, it will be apparent that the metering rod 60 and the piston 68 yare likewise prevented from moving in the direction of the left hand. Accordingly, it will be apparent that as the draft gear yoke 4 is moved in the direction of the left hand, the end plate 53, hydraulic draft gear cylinder 42, Vand the hydraulic liquid reservoir 48 which is welded to the cylinder 42 are moved therewith against the yielding iresistance of the spring 61, and with respect to `the piston 68, metering rod 60 and cup-shaped plunger 80, to simultaneously increase the volume of the chamber yand decrease the volume of therchambers 86 and 87. As this movement continues in the direction of the left hand, it is effective to force the oil in the chamber 86 to flow at a relatively high `velocity through the orice constituted by the bushing 62 through which the metering rod 60 extends to the chamber 85 to dissipate kinetic energy in the manner hereinbefore explained.

Movement of the hydraulic draft gear cylinder 42 in the direction of the left hand relative to the piston 68 is effective to decrease the volume of chamber 87 and increase the pressure of the -air in this chamber to absorb a part of the kinetic energy transmitted by the pull or jerk of the locomotive to the car coupler, it being under'- stood that this kinetic energy is changed or converted to potential energy and stored in the air under pressure in the chamber 87.

The compression of the spring 61 as the hydraulic draft gear cylinder 42 moves in the direction of the left hand is effective to change or convert a part of the kinetic energy resulting from the jerk exerted by the locomotive on the car coupler into potential energy and store it in spring 61.

Furthermore, the friction of the draft gear yoke "4 and the other moving parts of the mechanism are effective to dissipate or absorb some of this kinetic energy. Therefore, all of the kinetic energy transmitted to the coupler .and its shank on the train end of the locomotive and the coupler and its shank on the locomotive end of the first car in the train, with the exception of the potential ener-gy stored in the springs 61 and the air under pressure in the chambers 87, is dissipated in the form of heat in the manner hereinbefore explained, or is transferred as kinetic energy to the locomotive frame and, via the cup-shaped plunger 80 and follower 90, to the front draft lugs which are integral with the striker 20 that is welded to the center sill 22 of the first car -in the train.

The jerk delivered to the car coupler and shank 6 of the first car in the train as the result of the initial movement of the locomotive is effective to move the shank 6, draf-t gear yoke 4 and hydraulic draft gear cylinder 42 in the direction of the left hand, as viewed in the drawings, relative to the center sill 22, striker 20 and front draft lugs formed integral therewith, follower 90,

17 cup-shaped plunger 80, metering rod 60 and piston 68 until the left-hand face of the follower web 16, which is an integral part of the draft gear yoke 4, comes into contact with the piston rod 29 which, as hereinbefore stated, is now disposed in the elongated slot 19 (FIG. l) in the bot-tom of the chamber 18.

The remaining kinetic energy resulting from the jerk exerted on the hollow shank 6 of the coupler on that end of the first car adjacent the train end of the locomotive is transmitted through the piston rod 29, piston 26, interlock cylinder 23, and the striker 20, which is integral with the interlock cylinder 23, to the center sill 22. This remaining kinetic energy that is not absorbed by, the hydraulic draft gear device but is transmitted to the center sill 22 and car body of the first car in the train is effective to move this car from its standing position in the same direction as the initial movement of the locomotive. This movement of the first car in the train effects a relative acceleration between the body of the first car and the lading therein.

Since the piston rod 29 is now disposed in the elongated slot 19 as hereinbefore explained, the draft gear travel in draft as a result of the initial movement of the locomotive is considerably less (2f/s instead of 30) than the draft gear travel in buff as the result of a car being humped colliding with a standing car or string of cars. Accordingly, the amount of kinetic energy absorbed by and stored as potential energy in the draft gear device is correspondingly less. However, it must be remembered that the kinetic energy transmitted to the car coupler as a result of the initial movement of the locomotive is considerably less than the kinetic energy transmitted to the car coupler as the result of a moving car in a hump yard colliding with a standing car or string of cars.

When a brake application is effected on a train, the brakes on the cars adjacent the locomotive apply prior to the brakes on the cars farther back in the train, as is well known to those skilled in the art. Therefore, each car farther back in the train than the car adjacent the locomotive tends to overtake or run into the car ahead. This movement of one car relative to the adjacent car ahead causes the car coupler on each respective car to operate in buff. The buff operation of the draft gear device gear -associated with the car coupler of each car is the same as has been hereinbefore described in detail in connection with a moving car striking a standing car or string of cars in a humping operation except that the exterior end of the piston rod 29 on each car is now disposed in the corresponding elongated slot 19 to reduce the buff travel from maximum buff travel to an amount indicated by the legend Buff Travel in FIG. 1, it being noted that this is the same as the amount of draft travel.

It, for any reason, it is desired that the draft gear device of a car coupled into a train have a buff travel and a draft travel that is the same as the buff travel while the car is detached from a train for humping operation in a railroad classification yard, the handle 37 of the cutout cock 36 is turned from the position in which it is shown in FIG. 1 to the position indicated by the broken line 37a in FIG. 1 to close communication between the brake pipe 38 and the pressure chamber 33 and vent this chamber to atmosphere. When the pressure chamber 33 is thus vented, the spring 27 is rendered effective to move the piston rod 29' and piston 26 to the position shown in FIG. l. While the piston rod 29 and piston 26 occupy the position shown in FIG. l, the draft gear device will operate in buff in the manner hereinbefore described in detail in connection with a humping operation.

The draft gear will operate in draft in the manner hereinbefore described, except movement of the draft gear yoke 4 in the direction of the left hand is not limited by the follower web 16 coming into contact with the piston rod 29 but will continue in the direction of the left hand until the left-hand end of the hydraulic draft gear cylinder 42 abuts the right-hand side of the follower 90.

1S This increase in the draft gear travel provides a corresponding increase in the amount of kinetic energy that the draft gear can absorb in draft.

The operation of the draft gear devices associated with the car couplers at the adjacent ends of any two coupled cars in a train is the same as the operation of the draft gear device associated with the coupler at the train end of the locomotive and the draft gear device associated with the coupler at the locomotive end of the first car in the train. Therefore, a detailed description of the operation of the draft gears associated with the car couplers at the respective adjacent ends of two coupled cars is not deemed necessary.

Description-Figs. 6 and 7 According to a second embodiment of the invention, two coaxial and oppositely arranged interlock cylinder casings 107 and 10S, which are shown in detail in FIG. 7, replace the single interlock cylinder casing 23 shown in FIG. 1 to provide a draft gear device that functions substantially the same as the draft gear device shown in FIGS. l, 1A, 1B, 2, 3, 4 and 5, it being understood that FIG. 6, FIG. 1A and FIG. 1B when taken together such that the right-hand edge of FIG. 6 is matched with the lefthand edge of FIG. 1A and the right-hand edge of FIG. 1A is matched with the left-hand edge of FIG. 1B constitutes an elevational sectional view of a hydraulic draft gear device constructed in accordance with this second embodiment of the invention. Accordingly, like reference numerals have been used to designate the structure shown in FIGS. 6 and 7 which is identical with that shown in FIG. 1. Only such features of the structure and operation of the embodiment of FIGS. 6 and 7 which differ from that of the embodiment of FIG. 1, FIG. 1A, FIG. 1B, FIG. 2, FIG. 3, FIG. 4 and FIG. 5 will be hereinafter described.

According to the embodiment of the invention shown in FIGS. 6 and 7, the two interlock cylinder casings 107 and 108 are respectively welded or otherwise secured to the outside vertical faces of the American Association of Railroad Z-sections 40 and 41, adjacent the left-hand end thereof.

In assembling the draft gear device shown in FIGS. 6 and 7, after the hollow shank 6 of the car coupler has been secured to the draft gear yoke 4 by the -shank pin 10, as shown in FIGS. l and 3, a hollow box-like striker 109 that differs somewhat from the striker 20, shown in FIG. 1, is slipped over the right-hand end of the draft gear yoke 4 and moved in the direction of the left hand until the left-hand end of the striker is substantially in alingment with the left-hand end of the draft gear yoke 4 and allowed to rest in this position until the draft gear device is assembled in the manner hereinbefore explained in connection with the first embodiment of the invention. Subsequent to assembling the draft gear device, the striker 109 is moved from the position in which it was placed in the direction of the right hand, as viewed in FIGS. 6 and 7, along the yoke 4 until the right-hand end thereof can be inserted into the left-hand end of the center sill pocket 21 after which the striker 109 is pushed into the center sill pocket until it occupies the position in which it is shown in FIGS. 6 and 7. With the striker 109 in this position, it is welded to the left-hand end of the center sill 22 and to the interlock cylinder casings 107 and 108, as indicated in FIGS. 6 and 7.

As shown in FIG. 7, the hollow box-like striker 109 is provided with two spaced-apart vertical parallel walls 110 and 111. Formed respectively on the adjacent sides of the walls 110 and 111 are oppositely extending bosses 112 and 113 which are arranged coaxial with the interlock cylinder casings 107 and 108. The bosses 112 and 113 are provided respectively with bores 114 and 115 of equal diameter that are coaxial with bores 116 and 117 of the same diameter provided respectively in the spaced-apart vertical walls of the American Association of Railroads 8,1 1 Z-sections 40 and 41. It will be noted that the centers of the cylinder casings 107 and 10S and the bores 114, 115, 116 and 117 lie on a horizontal axis that is perpendicular to and intersects the horizontal longitudinal axis of the draft gear yoke 4.

The interlock cylinder' casings 107 and 108 are provided respectively with bores 118 and 119 in which are respectively slidably mounted iluid pressure actuated pistons 120 and 121.

Release springs 122 and 123 are respectively interposed between the respective pistons 120 and 121 and the outside vertical face of the respective American Association of Railroads Z-sections and 41. These springs serve to yieldingly bias the pistons and 121 and piston rods 124 and 125 respectively formed integral therewith to the position in which they are shown in FIG. 7.

Two packing cups 126 and 127 of the snap-on type are secured to the respective pressure faces of the pistons 120 and 121 and cooperate respectively with pressure heads 128 and 129 secured to the respective interlock cylinder casings 1117 and 108 by any suitable means (not shown) to form respectively pressure chambers 130 and 131 to each of which chambers fluid under pressure may be supplied from the brake pipe on the car in the same manner as explained in connection with the pressure chamber 33 shown in FG. 1 of the drawings.

As shown in FIG. 7, the striker 1119 is provided with a pair of front draft gear lugs 132 that are formed integral therewith. While the yoke 4 and the draft gear device carried therein occupy their normal position, the righthaud side of the front draft gear lugs 132 abut the respective left-hand side of the opposite end portions of the follower 90, as shown in FIG. 7.

The draft gear devices shown in FIGS. l to 5 inclusive and i'n FIGS. 6 and 7 are identical in construction, except as pointed out above.

The operation of the draft gear devices shown in FIGS. l to 5 inclusive and in FIGS. 6 and 7 is identical, except that when the brake pipe on the car provided with the draft gear device shown in FIGS. 7 and 8 is charged, uid under pressure is simultaneously supplied to the pressure chambers 130 and 131 whereupon the corresponding pistons 120 and 121 move in opposite directions against the yielding resistance of the respective springs -122 and 123 until the outer ends of the respective piston rods 124 and 125 are disposed within the corresponding parallel spaced-apart rectangular openings 19a in the draft gear yoke 4 to limit the movement of the yoke 4 and draft gear device carried therein in either direction from the position in which the yoke 4 is shown in FGS. 6 and 7.

Description-FIGS. 8, 8A, 8B and 9 In FIGS. 8, 8A, 8B and 9 is shown a variable travel cushioned draft gear device constructed in accordance with a third embodiment of the invention. gear device is suitable for use with a horizontal type of draft gear yoke such as that shown on page 656 of Car Builders Cyclopedia, 21st edition, published in 1961 by Simmons-Boardman Publishing Corporation.

As shown in FIG. 9 of the drawings and also on the above-mentioned page 656, a draft gear device is carried in an elongated yoke pocket 133 formed between parallel spaced-apart inside surfaces 134 and 135 on the side Walls of a horizontal type of draft gear yoke 136 that is disposed in a center sill pocket 137 of a center sill 138 that may be fabricated by welding together two oppositely arranged American Association of Railroads Z-sections 139 and 140. The horizontal type of draft gear yoke 136, as shown in FIG. 9, is supported by two parallel lspaced-apart longitudinally extending angle brackets 141 and 142 secured respectively to the inside vertical faces of the American Association of Railroads Z-sections 139 and by means such as a plurality of rivets 143, it being understood that the angle brackets 141 and 142 are not riveted to the respective Z-sections until the draft This draft 211 gear device has been assembled and placed in the draft gear yoke 136 as hereinafter described in detail.

To properly position the draft gear device in the center sill pocket 137, one of a pair of L-shaped rear draft lugs 144 each having a plurality of spaced-apart strengthening ribs 144a is weided to the underside of the upper feet of the Association of American Railroads Z-sections 139 and 14d that constitute the center sill 138, as illustrated in FiGS. 8B and 9. The other one of the pair of L-shaped rear draft lugs 144 is disposed between and adjacent the lower end of the inside faces of the vertical spaced-apart parallel walls of the Association of American Railroads Z-sections 139 and 14) and welded thereto.

As shown in FIG. 8, one end of a hollow box-like striker 145 is disposed in the left-hand end of the center sili pocket 137 and welded to the left-hand end of the center sill 138, as indicated by the reference numeral 146. A left-hand end wall 147 of the striker 145 is provided with a substantially square opening 148 the size of which is somewhat in excess of the size of the shank of a railway car coupler.

The hereinbefore-mentioned draft gear device and horizontal type of draft gear yoke 136 are constructed and assembled as follows:

First, the right-hand end of a bore 149 (FIG. 8B) in a cylinder 151) is provided, as by machining, with an internal screw thread portion 151 for receiving the external screw threads formed on a hollow spring seat 152 that has a plurality of arcuately arranged apertures 153, two of which appear in F1G. 8B of the drawings. Subsequent to assembling the spring seat 152 to the right-hand end of the hollow cylinder 1511, a piston and spring assembly for insertion into the hollow cylinder 151B is prepared in a manner now to be described.

First, one end of a hollow rod 154, the outside diameter of which is slightly less than the inside diameter of the hollow spring seat 152, is inserted into a counterbore 155 formed in a semi-eiliptical-shaped piston 156 and welded thereto. Next, a hollow plastic packing land 157 is placed so as to abut the right-hand side of the piston 156. Thereafter, a plurality of pieces of V-shaped packing 15S arranged in a stack is seated against the right-hand side of the plastic packing land 157. A second plastic packing land 159 is now positioned against the right-hand end of the stack of V-shaped packing 158 after which a packing gland nut 160 is screw threaded onto a threaded portion 161 of the piston 156 to clamp the Stack of pieces of V-shaped packing 158 tightly between the plastic packing lands 157 and 159.

The periphery of the packing gland nut 161B is provided with three spaced-apart peripheral annular grooves 162. Therefore, an O-ring seal 163 is now inserted in each of the peripheral annular grooves 162.

Following inserting the three `O-ring seals 163 in the corresponding peripheral annular grooves 162, a strong spring 164, constructed of' large diameter wire, is siipped over the end of the hollow rod 154 opposite the piston 156 and moved in the direction of the piston 156 untii the end of the spring adjacent the piston yabuts the righthand end of the packing gland nut 160.

After completing the operation of assembling the piston 156, hollow rod 154 and spring 164, the end of the hollow rod 154 remote from .the piston 156 and the corresponding end of the spring 164 are inserted into the end of the bore 149 in the cylinder 150 remote from` the spring seat 152 and then moved in the direction of the spring seat 152 until the packing gland nut 160 can be inserted into the bore 149 in the cylinder 150. Thereafter, the piston and spring yassembly are shoved into the cylinder 150 so that the right-hand end of the hollow rod 154 enters the hollow spring seat 152 and is moved to the position shown in FIG. 8B in which the right-hand end of the hollow rod 154 is Hush with the right-hand side of the hollow spring seat 152.

Subsequent to placing Vthe piston 156, hollow rod 154 

5. IN A RAILWAY CAR HAVING A CENTER SILL MEMBER AFFIXED TO THE BODY OF THE CAR AND PROVIDED WITH A DRAFT GEAR POCKET, AND DRAFT GEAR ASSEMBLY DISPOSED IN SAID DRAFT GEAR POCKET AND COMPRISING: (A) A DRAFT GEAR YOKE HAVING TWO SPACED-APART TRAVEL IN SAID DRAFT GEAR POCKET REATIVE TO THE CENTER SILL MEMBER RESPONSIVELY TO DRAFT AND BUFF FORCES EXERTED THEREON, SAID YOKE HAVING TWO SPACED-APART ELONGATED SLOTS, (B) A DRAFT GEAR DEVICE DISPOSED IN ONE OF SAID SLOTS AND COOPERATIVE WITH THE CENTER SILL MEMBER UPON EXERTION OF DRAFT AND BUFF FORCES ON SAID DRAFT GEAR YOKE TO ABSORB ENERGY TO A DEGREE PROPORTIONAL TO THE DISTANCE OF TRAVEL OF SAID DRAFT GEAR YOKE, (C) A FLUID PRESSURE CONTROLLED DEVICE SECURED TO THE CENTER SILL MEMBER IN A CERTAIN ALIGNED POSITION AND HAVING A PISTON AND PISTON ROD ACTUATED RESPONSIVELY TO A PREDETERMINED FLUID PRESSURE TO A POSITION IN WHICH THE PISTON ROD PROJECTS INTO THE OTHER OF SAID SLOTS IN SAID DRAFT GEAR YOKE WHEREBY THE PISTON ROD COOPERATES WITH THE YOKE TO CONTROL THE TRAVEL OF THE YOKE BETWEEN SAID CERTAIN MAXIMUM TRAVEL AND A CHOSEN MINIMUM TRAVEL AND THEREBY THE ENERGY ABSORBED BY SAID DRAFT GEAR DEVICE, (D) BIASING MEANS EFFECTIVE TO NORMALLY BIAS SAID PISTON AND PISTON ROD TO A POSITION IN WHICH THE PISTON ROD IS DISPOSED OUT OF THE OTHER OF SAID SLOTS IN SAID DRAFT GEAR YOKE TO PROVIDE FOR MAXIMUM TRAVEL OF SAID DRAFT GER YOKE, AND (E) A BRAKE PIPE OF A FLUID PRESSURE BRAKE SYSTEM, AN INCEASE IN THE PRESSURE IN WHICH IS EFFECTIVE TO CAUSE ACTUATION OF SAID PISTON AND PISTON ROD OF SAID FLUID PRESSURE CONTROLLED DEVICE AGAINST THE BIASING FORCE OF SAID BIASING MEANS TO THE POSITION IN WHICH THE PISTON ROD PROJECTS INTO THE OTHER OF SAID SLOTS IN SAID DRAFT GEAR YOKE TO PROVIDE FOR MINIMUM TRAVEL OF SAID GEAR YOKE AND A DECREASE IN PRESSURE IN WHICH IS EFFECTIVE TO CAUSE ACTUATION OF SAID PISTON AND PISTON ROD BY SAID BIASING MEANS TO THE POSITION IN WHICH THE PISTON ROD IS DISPOSED OUT OF THE OTHER OF SAID SLOTS IN SAID DRAFT GEAR YOKE TO PROVIDE FOR MAXIMUM TRAVEL OF SAID SHAFT GEAR YOKE. 